Imported existing code

libraries/include/boost/unordered/detail/move.hpp

@@ -0,0 +1,228 @@
+/*
+    Copyright 2005-2007 Adobe Systems Incorporated
+   
+    Use, modification and distribution are subject to the Boost Software License,
+    Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+    http://www.boost.org/LICENSE_1_0.txt).
+*/
+
+/*************************************************************************************************/
+
+#ifndef BOOST_UNORDERED_DETAIL_MOVE_HEADER
+#define BOOST_UNORDERED_DETAIL_MOVE_HEADER
+
+
+#include <boost/mpl/bool.hpp>
+#include <boost/mpl/and.hpp>
+#include <boost/mpl/or.hpp>
+#include <boost/mpl/not.hpp>
+#include <boost/type_traits/is_convertible.hpp>
+#include <boost/type_traits/is_same.hpp>
+#include <boost/type_traits/is_class.hpp>
+#include <boost/utility/enable_if.hpp>
+#include <boost/unordered/detail/config.hpp>
+
+/*************************************************************************************************/
+
+namespace boost {
+namespace unordered_detail {
+
+/*************************************************************************************************/
+
+namespace move_detail {
+
+/*************************************************************************************************/
+
+#if !defined(BOOST_UNORDERED_NO_HAS_MOVE_ASSIGN)
+
+/*************************************************************************************************/
+
+template <typename T>  
+struct class_has_move_assign {  
+    class type {
+        typedef T& (T::*E)(T t);  
+        typedef char (&no_type)[1];  
+        typedef char (&yes_type)[2];  
+        template <E e> struct sfinae { typedef yes_type type; };  
+        template <class U>  
+        static typename sfinae<&U::operator=>::type test(int);  
+        template <class U>  
+        static no_type test(...);  
+    public:  
+        enum {value = sizeof(test<T>(1)) == sizeof(yes_type)};  
+    };
+ };  
+
+/*************************************************************************************************/
+
+template<typename T>
+struct has_move_assign : boost::mpl::and_<boost::is_class<T>, class_has_move_assign<T> > {};
+
+/*************************************************************************************************/
+
+class test_can_convert_anything { };
+
+/*************************************************************************************************/
+
+#endif // BOOST_UNORDERED_NO_HAS_MOVE_ASSIGN
+
+/*************************************************************************************************/
+
+/*
+    REVISIT (sparent@adobe.com): This is a work around for Boost 1.34.1 and VC++ 2008 where
+    boost::is_convertible<T, T> fails to compile.
+*/
+
+template <typename T, typename U>
+struct is_convertible : boost::mpl::or_<
+    boost::is_same<T, U>,
+    boost::is_convertible<T, U>
+> { };
+
+/*************************************************************************************************/
+
+} //namespace move_detail
+
+
+/*************************************************************************************************/
+
+/*!
+\ingroup move_related
+\brief move_from is used for move_ctors.
+*/
+
+template <typename T>
+struct move_from
+{
+    explicit move_from(T& x) : source(x) { }
+    T& source;
+};
+
+/*************************************************************************************************/
+
+#if !defined(BOOST_UNORDERED_NO_HAS_MOVE_ASSIGN)
+
+/*************************************************************************************************/
+
+/*!
+\ingroup move_related
+\brief The is_movable trait can be used to identify movable types.
+*/
+template <typename T>
+struct is_movable : boost::mpl::and_<
+                        boost::is_convertible<move_from<T>, T>,
+                        move_detail::has_move_assign<T>,
+                        boost::mpl::not_<boost::is_convertible<move_detail::test_can_convert_anything, T> >
+                    > { };
+
+/*************************************************************************************************/
+
+#else // BOOST_UNORDERED_NO_HAS_MOVE_ASSIGN
+
+// On compilers which don't have adequate SFINAE support, treat most types as unmovable,
+// unless the trait is specialized.
+
+template <typename T>
+struct is_movable : boost::mpl::false_ { };
+
+#endif
+
+/*************************************************************************************************/
+
+#if !defined(BOOST_NO_SFINAE)
+
+/*************************************************************************************************/
+
+/*!
+\ingroup move_related
+\brief copy_sink and move_sink are used to select between overloaded operations according to
+ whether type T is movable and convertible to type U.
+\sa move
+*/
+
+template <typename T,
+          typename U = T,
+          typename R = void*>
+struct copy_sink : boost::enable_if<
+                        boost::mpl::and_<
+                            boost::unordered_detail::move_detail::is_convertible<T, U>,                           
+                            boost::mpl::not_<is_movable<T> >
+                        >,
+                        R
+                    >
+{ };
+
+/*************************************************************************************************/
+
+/*!
+\ingroup move_related
+\brief move_sink and copy_sink are used to select between overloaded operations according to
+ whether type T is movable and convertible to type U.
+ \sa move
+*/
+
+template <typename T,
+          typename U = T,
+          typename R = void*>
+struct move_sink : boost::enable_if<
+                        boost::mpl::and_<
+                            boost::unordered_detail::move_detail::is_convertible<T, U>,                            
+                            is_movable<T>
+                        >,
+                        R
+                    >
+{ };
+
+/*************************************************************************************************/
+
+/*!
+\ingroup move_related
+\brief This version of move is selected when T is_movable . It in turn calls the move
+constructor. This call, with the help of the return value optimization, will cause x to be moved
+instead of copied to its destination. See adobe/test/move/main.cpp for examples.
+
+*/
+template <typename T>
+T move(T& x, typename move_sink<T>::type = 0) { return T(move_from<T>(x)); }
+
+/*************************************************************************************************/
+
+/*!
+\ingroup move_related
+\brief This version of move is selected when T is not movable . The net result will be that
+x gets copied.
+*/
+template <typename T>
+T& move(T& x, typename copy_sink<T>::type = 0) { return x; }
+
+/*************************************************************************************************/
+
+#else // BOOST_NO_SFINAE
+
+// On compilers without SFINAE, define copy_sink to always use the copy function.
+
+template <typename T,
+          typename U = T,
+          typename R = void*>
+struct copy_sink
+{
+    typedef R type;
+};
+
+// Always copy the element unless this is overloaded.
+
+template <typename T>
+T& move(T& x) {
+    return x;
+}
+
+#endif // BOOST_NO_SFINAE
+
+} // namespace unordered_detail
+} // namespace boost
+
+/*************************************************************************************************/
+
+#endif
+
+/*************************************************************************************************/